Material feeding apparatus



' Nov.v24, 1959 o.J. RICHTER MATERIAL FEEDING APPARATUS Filed March 10,1958 3 Sheets-Sheet 1 Nov. 24, 1959 l o. J. RICHTER A 2,914,223

' I MATERIAL FEI-:DING APPARATUS Filed March 1o, 1958 s-sheetsneet l2`ffy. 2

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Nov. 24, 1959 o. J. RICHTER Y 2,914,223

MATERIAL FEEDING APPRATUS Filed March 1o, 1958 s sheets-sheet s UVM/V705@4,5 C/o/M/v Wwf/753 c i 2,914,223 .Ice Patented Nov. 24, 1959 2,914,223MATERIAL FEEDING APPARATUS Ole Johan Richter, Facture, France, assignorto Aktieolaget Kamyr, Karlstad, Sweden, a company of we en ApplicationMarch '10, 1958, Serial No. 720,494 Claims priority, application SwedenMarch 11, 1957 3 Claims. (Cl. 222194) The present invention relate-s tomaterial feeding apparatus. More particularly, it relates to a chargingvalve device for feedingr comminuted cellulosic liber material, such aswood chips, straw, etc., into a pressure vessel, particularly into acontinuous cellulose digester.

Known charging valve devices of the above character usually include ahousing having ports, and a valve body rotatable in the housing andhaving one or more passageways, bores or pockets extending transverselytherethrough for sequential communication with an inlet port and anoutlet port of the housing. Such known devices are usually furthercharacterized in that the housing is provided with a third port adaptedto be periodically put in communication with the outlet port throughsaid valve body passageway for periodic flow through said passageway ofsteam or other suitable hot uid discharging the material in the valvepassageway through said outlet port.

The object of the invention is to improve the emptying of thepassageways or pockets of such Valve devices so that they can be emptiedby means of a comparatively small quantity of high-pressure fluid, suchas Steam, preferably by means of a quantity less than the steam quantityrequired for the heating of the material to the digesting temperature.According to the invention, this object is attained by providing thatthe steam or other suitable hot fluid is brought to flow through thepocket or passageway of the valve device during a short time intervaland with a speed as high as possible, i.e., as an explosion-like puff orblast, whereby the carrying force exerted by the steam ow upon thecharge of material in the valve passageway is of extremely highmagnitude. ln this connection, it has been found to be essential toutilize a steam container of considerably larger volume than that of thevalve body passageway in the immediate vicinity of and in communicationwith the aforesaid third port of the charging valve device. The volumeof this container should be at least times and preferably 20 to 50 timesas large as the volume of a passageway in the charging valve device.Thus, the steam quantity required for emptying the passageways is madeconveniently and readily available on the spot, this being aprerequisite for obtaining the desired forceful puff or blast.

lt has further been found that if'the steam or other hot fluid containeris connected to the aforesaid third port of the housing by means of aconduit having a cross sectional area several times as large as that ofthe inlet feed linethrough which the hot fluid is supplied to thecontainer, a low flow resistance in the conduit to the charging valvedevice is created. Such low resistance promotes a quick discharge fromthe container through said conduit. This latter feature has theadvantage that a, continuous and even flow will thus be maintained insaid conduit and the pressure variations therein, particularly in itsfar end, will be small, this being significantly important especiallywhen the not iluid is steam tapped from a steam turbine.

In a preferred embodiment of the invention, there is inserted in theconduit between the steam container and the charging valve device aquick-acting valve, the maximum admission cross sectional area of whichis at least equal to one-half of the cross sectional area of the conduitfrom the container. Preferably, said quick-acting valve is operated bypressure fluid and is controlled in accordance with rotation of thevalve body of the charging valve. This quick-acting valve allows apractically unrestricted flow during the' whole admission time period,said period being kept very short and correctly timed relatively to theposition of the passageway or passageways in the charging valve body sothat the dynamic action of a certain or predetermined quantity of thehot fluid or steam will be at a maximum.

Other objects and advantages of the invention will be evident from thefollowing description and accompanying drawings, in which:

Figure l is a fragmentary, diagrammatic and partially sectionedelevational view of a continuous cooking plant equipped with a feedingapparatus embodying the invention;

Figures 2 and 3 are corresponding fragmentary and enlarged verticalsectional views of the charging valve device of Figure l and showingdifferent-operative positions thereof; and

Figure 4 is a sectional view taken along line IV-IV of Figure 3, andwith certain parts being omitted for the sake of clarity and convenienceof illustration.

Referring now to the drawings, Figure l shows a cooking plant providedwith an illustrative embodiment of the material feeding apparatus of theinvention. Numeral 11 designates an upright cylindrical digester, theupper end of which should be charged continuously with a heated mixtureof a comminuted cellulosic fiber material, for example, wood chips,straw, etc., and a suitable digesting liquor, for example, sodium lye.From the bottom of the digester (not shown) the material is dischargedcontinuously at such arate -that a level 13 is maintained somewhat belowthe upper end of the digester, the rest of the digester being filledwith steam. Connected to the upper end of the digester is a heatingvessel 17 having a feeding screw 15 therein, as shown, and in whichvessel the material, while being stirred, is heated by `steam to thetemperature required for the digesting cook, before the material isdelivered into the digester. A raised pressure which can be of the orderof 8 atmospheres gauge may be present in the digester 11 and the vessel17. Additionally, the temperature in the digester may be around to 200C.

The liber material preferably is charged against the pressure in thevessel 17 by means of a charging valve device constructed in accordancewith the invention. Said valve device, as shown, includes a housing 19and a cylindrical or somewhat frusto-conical rotor or valve body 21turnable or rotatable therein (see Figures 1 and 4).' A horizontal shaft23 projects from the rotor 21 and is journalled in bearings 25, 27suitably mounted on either side of the housing 19 as by spider frames,as shown in Figure 4.

In the illustrated form, the valve body 21 is formed with twoaxially-spaced passageways o r pockets 29,' 31 therein. Thesepassageways preferably are disposed at right angles to each other andextend diametrically through the valve body. Each passageway forms astraight passage which is somewhat widened at the middle (see Figures 2and 3) and preferably is of a generally rectangular cross section.The'housing 19, as illustrated, has four ports 33, 35, 37 and 39 which,in the axial direction of the valve body 21, extend across the twopassageways 29, 31 (see Figure 4). The ports preferably are arranged inpairs, opposite each other,

and adjacent ports are displaced approximately 90 degrecs in theperipheral or circumferential direction relatively to each other. Port33 is an inlet port and is placed in communication With the bottom of alow-pressure steaming vessel 43 via a vertical passage 41. A feedingscrew 45 may be provided in vessel 43, as indicated.

The mixture of comminuted fibrous material and the digesting liquor ischarged into the hopper 47 from which it is introduced into vessel 43 byany suitable means, such as the rotary charging device 49. The materialis heated in vessel 43, preferably by steam, after which it flowsthrough the passage 41 and into the inlet 33. When the valve bodypassage 31 takes the position shown in Figure 1, the material collectedinl the inlet 33 drops down and fills this passageway. Connected to theport 37 is a conduit 51 leading to the upper part of the vessel 43 andserving the purpose of equalizing the pressure on the valve body 21. Ascreen 53 (see Figure 2) covers port 37 and prevents the solid materialin passageway 31 from entering the conduit 51. Y

The port 35 forms the outlet port of the charging valve device and isconnected by the elbow conduit section 55 to the heating vessel 17, asshown. When the valve body 21 is turned from its Figure 1 position andin the direction of the arrow in Figures 2 and 3, the lled passageway 31will be sequentially shut off from the inlet 33 and then put intocommunication with the outlet port 35 under high pressure. When thispassageway reaches the position shown in Figure 2, it will be emptied ina manner to be described in more detail by steam supplied through theport 39.

The invention contemplates that a container 57 be arranged in theimmediate vicinity of the charging valve device. This container isconstructed and arranged to be filled with high-pressure steam supplie-dthrough a conduit 59 (Figure l). The far end of said conduit preferablyis connected either to a boiler or some other steam generator or to asteam turbine (none of which is shown), from which steam of a suitablepressure is tapped otf for flow to container 57. In the container 57 apressure is maintained which is somewhat higher than the pressure of thedigester 11, for example, such pressure in container 57 may be around 10to 12 atmospheres gauge. Preferably, the conduit 59 is made relativelynarrow, so that a considerable pressure drop will be produced therein.The container 57 is connected to the port 39 of the charging valvedevice by means of a comparatively short and wide conduit means 61, 63.lnserted in this conduit means is a valve 65, the maximum admissioncross-sectional area of which is approximately of the same size as thecross-sectional area of the conduit part 61, or in any case at leastgreater than half of the cross-sectional area of conduit 61. In thisregard, the conduit 63 widens in the direction toward the port 39, andwhen the passageway 31 is in the position shown in Figure 2 and thevalve 65 is fully opened, a uid flow path having an extremely lowresistance to ow will thereby be provided between the steam container 57and the vessel 17 through Vconduit means 61, 63, valve 65, passageway 31and conduit 55.

The illustrative embodiment of valve 65, as best seen in Figures `2 and3, preferably is provided with a valve body in the shape of a hollowcylindrical slide 67 reciprocably arranged in a cylindrical llining 69inserted in the valve housing and having admission or flow slits 71therein. The slide, as shown, has upper and lower openings therein andis displaceable between an upper, opened position (Figure 2), in whichthe slits 71 are wholly uncovered, and a lower, closed position (Figure3), in which the slits are covered by the slide. The lining 69 forms aush extension of the conduit 61, said conduit 'opening out into one endof the lining. Between the valve housing wall and the slitted part ofthe lining there is an annular space 73 communicating with the conduitpart 63, as indicated.

The slide 67 preferably is operated by a pneumatic cylinder 75 (Figure2) and a piston 77 movable therein. A piston rod 79 connects the piston77 to the slide. Pressure uid is supplied to cylinder 75 through aconduit 81 and is directed by an appropriate reversing valve 83alternately to one end of the cylinder 75 and then thc other. Actuationof valve 83 preferably is controlled by a suitable impulse means 85which, in turn, is actuated by cam lobes 87 on a cam disc 89 attached tothe shaft 23 projecting from valve body 21 (see Figures 2 and 4).

Immediately before the valve body 21 arrives at the position shown inFigure 2, the impulse means 85 is actuated by a cam lobe 87, asindicated, thereby reversing the valve 33 and admitting pressure fluidto the lower end of the cylinder 75. The piston 77 is then rapidly movedby such pressure uid to the upper end position thereof shown in Figure2, carrying with it the valve slide 67, so that the slits 71 are whollyuncovered. After a turning movement of the valve body of merely a fewdegrees, the cam lobe 87 in question will have passed out of contactwith the impulse means 85, and this means then will return to its normalrest position causing reversal of the valve 83 and a consequent ow ofpressure fluid into the upper end of cylinder 75. This results in rapidmovement of the piston 77 downwardly to the position shown in Figure 3,thereby effecting closure of valve slide 67. At a normal angularVelocity of the valve body 21 of about 3 to l0 revolutions per minute,the valve 65 will be held open during an interval of 0.25 to 0.5 second.During this short interval, a powerful and fast moving volume of steamis admitted from the container 57 through conduit 61, valve 65, conduit63, pocket 31 and passage 55. This steam flow meets with no appreciableresistance until it reaches passageway 31, where the steam penetratesthe spaces between the particles of the charge in the passageway,exerting ya force of great magnitude thereon, so that the charge israpidly and conipletely driven out of the passageway and through theconduit 55 for discharge into the vessel 17.

After the charged valve passageway 31 has been thusly emptied of itscharge of fibrous material, further rotation of the valve body 21 causespassageway 31, now filled with high-pressure steam, to be initially shutolf at both ends and then to be brought lto the position thereof shownin Figure 3, in which the passageway is opened towards the inlet port33. The steam captured in the passageway now expands to the lowerpressure of the steaming vessel 43, the steam being conveyed to thissteaming vessel by means of a partition arrangement 91 inserted in theport 33 and passage 41, and extending upwardly into the steaming vessel.By virtue of this arrangement, the steam will liow from passageway 31 tothe vessel 43 without dispersing the iibrous material collected in theinlet 33 on the opposite side of partition 91. Finally, the passageway31 will be returned to the charging position thereof shown in Figure l,whereafter the aforedescribed cycle will be repeated. It will beappreciated that passageway 29 will be charged and emptied in the samemanner as that described for passageway 31, but with a time lagcorresponding to a rotary movement of the valve body 21 of 90. Thus, thesequential charging and discharging operations for the passageway 29will be 90 out of phase with respect to lthose for passageway 31. Theshort steam blasts or puffs coming from the steam container 57 pass:alternately or sequentially through the passageway 29 and passageway 31and, as is evident, during each revolution of the valve body 21 fourseparate charges will be transferred from the low to the high pressureside through passageways 29, 31.

In order to completely empty the valve passageways 29, 31, each steampuff or blast passing therethrough must 'be of `a volume of at leastabout twice as large as the volume of each passageway, preferably to 10times larger than the volume of the passageway. It is advantageous tomaintain an over-pressure in the container S7 as compared to thedigester pressure, and therefore, the volume of the container is made afew times, for example, 2 to 5 times, larger than the volume of eachblast of steam.

Branching off from the steam supply tube 59 is a tube 93 leading intothe side of the passage 55, as shown in Figure 1. Inserted in tube 93 is.a valve 95 controlled by a suitable temperature-sensitive means 9/arranged in the digester wall and operatively connected to the valve 95.Of the steam required for heating the fibrous material in the Vessel 17,a large and almost constant part passes through the body 21 of thecharging valve device. However, the desired temperature of the digester11 can be maintained by controlling that part of the steam passingthrough the tube 93. Thus, even when the steam consumption is as low as0.5 kgs. per ton of dry pulp produced, only a part of the total quantityof steam need be used for emptying the passageways 29, 31 of thecharging valve device.

It will thus be seen that the objects of this invention have been fullyand electively accomplished. It will be realized, however, that theforegoing specific embodiment has been shown and described only for thepurpose of illustrating the principles of the invention and are subjectto extensive change Without departure from such principles. Therefore,this invention includes all modications encompassed within the spiritand scope oi the appended claims.

I claim:

1. Apparatus for feeding fibrous materials or the like into a pressurevessel, said apparatus comprising: a valve housing having spacedmaterial inlet and outlet ports; a valve body rotatably mounted in saidhousing being provided with at least one passageway extendingtransversely therethrough; means for rotating said valve body forsequentially disposing said passageway in commun-ication with saidspaced inlet and outlet ports; said housing also having a third portarranged for communication with said outlet port through said passagewayof said valve body; a container for hot uid under pressure; saidcontainer being arranged in the immediate vicinity of said third portand having a volume considerably greater than the volume of saidpassageway of said valve body; conduit means connecting said containerto said third port; a quick-acting valve arranged in said conduit meansbetween said container and said third port, the maximum admissioncross-sectional area of said latter valve being at least equal toone-half the cross-sectional area of said conduit means between saidcontainer and said latter valve; fluid pressure actuated meansoperatively connected to said quick-acting valve and said rotatablevalve body, said uid pressure means being operable in response torotation of said valve body to periodically actuate said quick-actingvalve.

2. Apparatus as defined in claim 1 wherein said uid pressure actuatedmeans operates to periodically open said quick-acting valve forapproximately 0.25 to 0.50 second.

3. Apparatus for feeding brous materials or the like into a pressurevessel, said apparatus comprising: a valve housing having spacedmaterial inlet and outlet ports; a valve body rotatably mounted in saidhousing being provided with at least one passageway extendingtransversely therethrough; means for rotating said valve body forsequentially disposing said passageway in communication with said spacedinlet and outlet ports; said housing also having a third port arrangedfor communication with said outlet port through said passageway of saidvalve body; a container for hot fluid under pressure; said containerbeing arranged in the immediate vicinity of said third port and having avolume considerably greater than the volume of said passageway of saidvalve body; conduit means connecting said container to said third port;a quick-acting valve arranged in said conduit means between saidcontainer and said third port, the maximum admission cross-sectionalarea of said latter valve being at least equal to one-half thecross-sectional area of said conduit means between said container andsaid latter valve; means for eifecting a periodic discharge of a blastor puff of fluid from said container through said quick-acting valve andsaid conduit means, said blast of fluid having a volume approximately 5to 10 times as large as the volume of said passageway in .said valvebody.

References Cited in the le of this patent UNITED STATES PATENTS2,151,511 Hagen Mar. 21, 1939 2,299,565 Colburn Oct. 20, 1942 2,356,737Bland Aug. 29, 1944 2,644,724 Kronstad July 7, 1953

